Multiple plane scanning system for data reading applications

ABSTRACT

An optical system and method for data reading. The preferred system is directed to a scanner which includes a laser diode and a beam splitter for generating first optical beam and a second optical beam, the first optical beam being directed toward one side of a scanning optical element such as a rotating polygon mirror and to a first mirror array, the second optical beam is being simultaneously directed toward a second optical element such as another side of the rotating polygon mirror and then to a second and a third mirror array. The first mirror array is configured to generate a scan pattern through a vertical window and the second and third mirror arrays are configured to generate scan patterns passing through a horizontal window. In combination, the three mirror arrays generate three sets of scan lines so as to scan the bottom and all lateral sides of an object being passed through the scan volume.

RELATED APPLICATION DATA

[0001] This application is a continuation of application Ser. No.09/078,196, filed May 13, 1998, which is a divisional of applicationSer. No. 08/806,194, filed Feb. 26,1997, which issued as U.S. Pat. No.5,837,988, which is a divisional of application Ser. No. 08/554,819,filed Nov. 7, 1995, which issued as U.S. Pat. No. 5,705,802, which is adivisional of application Ser. No. 08/155,112, filed Nov. 19, 1993,which issued as U.S. Pat. No. 5,475,207, which is a continuation-in-partof application Ser. No. 07/913,580, filed Jul. 14, 1992, now abandoned.

BACKGROUND OF THE INVENTION

[0002] The field of the present invention relates to optical scanningsystems and particularly to a scanning system capable of successfullyreading objects aligned in a variety of orientations. The invention isespecially suitable for use as a fixed scanner such as that employed ata supermarket checkout counter reading bar codes such as those found onconsumer products.

[0003] For effective and accurate performance, a bar code scannerdepends upon focused optics and scanning geometry. Fixed scannersfrequently employ a rotating polygon mirror which directs a scanningbeam toward a mirror array for generating a desired scan pattern. Onetype of fixed bar code scanner positions a scan engine in a base with ascan window oriented in a horizontal plane. One such scanning system isdisclosed in U.S. Pat. No. 5,073,702 in which a scanning beam isreflected off a mirror array which has a plurality of mirrors arrangedin a generally semicircular pattern. The scanning beam reflecting offeach of the mirrors has vertically upward component thereby passingthrough the window/aperture. Objects to be scanned are passed over thewindow with the bar codes oriented in a generally downward direction.

[0004] In another scanner orientation, the scan engine is housed in avertical tower with the scan window oriented in a vertical plane. Insuch a vertical scanner, generally all the outgoing scan beams come outsidewards also have an upward vertical component. Objects to be scannedare passed in front of the window with the bar codes oriented in agenerally sideward direction.

[0005] In order to produce a successful scan, an object must be orientedwith its bar code passed in front of the scan window at an angle whichis not so oblique as to prevent a scan line from striking or “seeing”the bar code. Therefore to achieve a successful scan, the user mustposition the object with the bar code placed sufficiently close to thedesired orientation. The range of suitable plane orientation of theobject bearing the bar code is limited by the size of the window and theangle over which the mirror array can direct a scan pattern. Presentvertical scanners can scan bar codes oriented on certain lateral sides(i.e. side facing) which face the vertical window, but experiencedifficulties in scanning faces oriented in a horizontal plane (i.e.,facing up or down) or lateral sides opposite the window. Horizontalscanners (i.e. upward facing) are fairly adept at scanning the bottomside but are frequently limited as to which lateral sides may bescanned. The present inventors have recognized that it would bedesirable to increase the range of plane orientation readable by ascanning which would minimize required bar code label orientation,support belt to belt (automatic) scanning, and otherwise provide forimproved scanning ergonomics.

SUMMARY OF THE INVENTION

[0006] The present invention relates to an optical system and method fordata reading. A first preferred system is directed to a scanner whichincludes means for generating a first optical beam and a second opticalbeam, the first optical beam being directed toward one side of a firstscanning optical element such as a rotating polygon mirror and to afirst mirror array, the second optical beam being directed toward asecond scanning optical element such as another side of the rotatingpolygon mirror and then to a second mirror array. The first mirror arrayis configured to generate a scan pattern having an apparent source fromone orthogonal direction and the second mirror array is configured togenerate a scan pattern having an apparent source from anotherorthogonal direction. A second preferred system is directed to a scannerhaving a housing with a generally vertical window in an upper housingsection and a generally horizontal window in a lower housing section.The scanner includes a light source generating a light beam and a beamsplitter dividing the light beam into a first optical beam and a secondoptical beam. The first optical beam is directed toward one side of ascanning optical element, then to a first mirror array located in theupper housing section adjacent the vertical window, and then out thevertical window. The second optical beam is directed toward another sideof the scanning optical element with a first portion of the secondoptical beam being directed to a second mirror array located in a firstside of the lower housing section adjacent the upper housing portion andthen through the horizontal window and with a second portion of thesecond optical beam being directed to a third mirror array located in asecond side of the lower housing opposite the first side thereof. In apreferred embodiment, return signals detected from both the first andsecond optical beams are processed by a single microprocessor to allowfor unified signal processing.

[0007] Additional aspects and advantages of this invention will beapparent from the following detailed description of preferredembodiments, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIG. 1 is a front perspective view of a vertical multiplanescanner according to the present invention;

[0009]FIG. 2 is a partially diagrammatic right side elevation view ofthe scanner of FIG. 1;

[0010]FIG. 3 partially diagrammatic top plan view of the scanner of FIG.1;

[0011]FIG. 4 partially diagrammatic front side elevation view of thescanner of FIG. 1;

[0012]FIG. 5 is a diagrammatic top plan view of the scan pattern along ahorizontal plane generated from the upper mirror array of the scanner ofFIG. 1;

[0013]FIG. 6 is a diagrammatic front side elevation view of the scanpattern along a vertical plane generated from the lower mirror array ofthe scanner of FIG. 1;

[0014]FIG. 7 is a schematic diagram illustrating a preferred polygonmirror scanning and collecting configuration;

[0015]FIG. 8 is a schematic diagram illustrating an alternate polygonmirror light scanning and collecting configuration;

[0016]FIG. 9 is a schematic diagram illustrating another alternatepolygon mirror scanning and collecting configuration;

[0017]FIG. 10 is a detailed view of the shutter of FIG. 9 taken alongline 10-10;

[0018]FIG. 11 is a schematic diagram illustrating another alternatepolygon mirror scanning and collecting configuration;

[0019]FIG. 12 is a schematic diagram illustrating another alternatepolygon mirror scanning and collecting configuration;

[0020]FIG. 13 is a schematic diagram illustrating another alternatepolygon mirror scanning and collecting configuration;

[0021]FIG. 14 is a schematic diagram illustrating an alternate lightscanning and collecting configuration using an pair of movable mirrors;

[0022]FIG. 15 is a schematic diagram illustrating a holographic disklight scanning and collecting configuration;

[0023]FIG. 16 is a schematic diagram illustrating an alternateholographic disk light scanning and collecting configuration;

[0024]FIG. 17 is a schematic diagram illustrating a dual holographicdisk light scanning and collecting configuration;

[0025]FIG. 18 is a flow chart of a preferred light scanning andcollecting processing scheme;

[0026]FIG. 19 is a flow chart of an alternate light scanning andcollecting processing scheme;

[0027]FIG. 20 is a front perspective view of a combination vertical andhorizontal scanner;

[0028]FIG. 21 is a top right side perspective view of an alternatemultiplane scanner according to the present invention;

[0029]FIG. 22 is a simplified schematic of the optics of the scanner ofFIG. 21;

[0030]FIG. 23 is a diagrammatic side view of the internal optics of thescanner of FIG. 21;

[0031]FIG. 24 is a side elevation view of the internal optics of thescanner of FIG. 21;

[0032]FIG. 25 is a top right side perspective view of the scanner ofFIG. 21 in partial cutaway;

[0033]FIG. 26 is a diagrammatic view of the scan pattern along avertical plane generated from the upper mirror array of the scanner ofFIG. 21;

[0034]FIG. 27 is a diagrammatic view of the scan pattern along avertical plane generated from the lower mirror array of the scanner ofFIG. 21;

[0035]FIG. 28 is a diagrammatic view of the scan pattern along ahorizontal plane generated from the lower mirror array of the scanner ofFIG. 21; and

[0036]FIG. 29 is a flow chart of preferred light scanning and collectingprocessing schemes for the scanner of FIG. 21.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0037] The preferred embodiments will now be described with reference tothe drawings. FIG. 1 is a schematic diagram of a preferred verticalscanner 10 having a housing 12 with a lower housing portion 14 and anupper housing portion 16.

[0038] The scanner 10 generates a scan volume generally designated 5 byscanning beams projected outwardly through lower and upper windows 20and 25. In order to facilitate referral to relative directions,orthogonal coordinates (X, Y, Z) are designated in FIG. 1. The Xcoordinate is defined as a sideways direction, perpendicular to orhorizontally outward from the lower window 20 of the scanner housing 12;the Y coordinate is defined as a vertically upward direction; and the Zcoordinate is defined as another horizontal direction parallel to thelower window 20.

[0039] FIGS. 2-4 illustrate the internal scanning beam generation andcollection configuration of the scanner 10. The scanner 10 has twowindows namely a lower window 20 and an upper window 25 arranged at anoblique or inclined angle to one another. The scanner 10 may alternatelyhave a single vertical or inclined window, but the dual windowconfiguration provides physical information to the user regarding thedirection of the scanning beams, namely that one scanning beam patternis generally emanating from the upper window 25 and one scanning beampattern is generally emanating from the lower window 20.

[0040] The scan engine of scanner 10 has a central rotating polygonmirror 30 driven by a motor 40. In the lower housing portion 14, a lightsource 76 generates a beam of light and directs it toward mirror 74. Thelight source 76 may be a laser, laser diode, or any other suitablesource. The mirror 74 focuses and reflects light toward the polygonmirror 30 which has four mirror facets 31, 32, 33, 34. As the polygonmirror 30 rotates, the outgoing beam is directed across the lower mirrorarray 80 and then reflected out through the lower window 20 to achieve adesired scan pattern. Light reflecting off the target returns via thesame path and is collected by a collection mirror 72 and focused onto adetector 79. The polygon mirror 30 is preferably molded in a singlepiece out of emanating, but could be constructed out of acrylic or otheroptical materials including other plastics, metals or glass by oneskilled in the art. The outer surface of each mirror facet may beadvantageously coated with a suitable high reflective coating, thecoating chosen would depend upon the optical material of the polygonmirror 30. For example, a emanating or acrylic facet may have a metalliccoating such as aluminum or gold, while a metal or glass facet may bepreferably coated with a single or multi-layered dielectric such assilicon dioxide (SiO₂) or titanium dioxide.

[0041] The outgoing beam mirror 74 and the incoming collection mirror 72are also preferably an integral unit of one-piece construction forming amirror unit 70. Both mirror elements are optically powered, the smalleroutgoing mirror 74 being parabolic and the larger collection mirror 72being ellipsoidal.

[0042] Simultaneously (or intermittently if desired) to the operation ofthe lower scan generation, an upper light source 56 generates a beam oflight and directs it toward mirror 54. The light source 56 may be alaser, laser diode, or any other suitable source. The mirror 54 focusesand reflects light toward the polygon mirror 30. As the polygon mirror30 rotates, the outgoing beam is directed across the upper mirror array60 and then reflected out through the upper window 25 to achieve adesired scan pattern. Light scattered off the target returns the samepath and is collected by a collection mirror 52, reflecting off foldmirror 58 and focused onto a detector 59. The outgoing beam mirror 54and the incoming collection mirror 52 are preferably an integral unit ofone-piece construction forming a mirror unit 50. Both mirror elementsare optically powered, the smaller outgoing mirror 54 being parabolicand the larger collection mirror 52 being ellipsoidal.

[0043] Outgoing light beam from the upper source 56 reflects off oneside of the polygon mirror 30 while simultaneously the light beam fromthe lower source 76 reflects off an opposite side of the polygon mirror30. The upper mirror array 60 cooperates with the rotating polygonmirror 30 to generate the scan pattern 90 shown in FIG. 5. FIG. 5 is adiagrammatic top plan view of a scan pattern 90 of intersecting scanlines 92 as shown in a horizontal X-Z plane at the base of the scanner10.

[0044] The lower mirror array 80 cooperates with the rotating polygonmirror 30 to generate the scan pattern 95 shown in FIG. 6. FIG. 6 is adiagrammatic front elevation view of a scan pattern 95 of intersectingscan lines 97 as shown in a vertical Y-Z plane located at a distance of6.0 in. (15.24 cm) from the scanner 10. From the above description andthe scan patterns disclosed, one skilled in the art may construct asuitable polygon mirror 30 and mirror arrays 60, 80 to achieve thedesired scan patterns.

[0045] As shown in FIGS. 2-4, the mirror arrays 60, 80 comprise aplurality of pattern mirrors arranged generally in what may be describedas a semi- circular or oval pattern. The pattern mirrors may beconfigured to produce a multitude of desired scan patterns. The scanner10 projects scanning sweeps along two generally orthogonal directions,one scanning sweep emanating generally downwardly and sidewardly fromthe upper inclined window 25 and one scanning sweep emanating generallysidewardly and upwardly from the vertical lower window 20. It is thecooperation of these two scanning sweeps emanating from differentscanning directions which result in enhanced scanning range. The mirrorarrays 60, 80 may be designed to produce a desired scan pattern for aparticular application.

[0046] The upper window 25 is arranged at an oblique angle Θ to thevertical lower window 20 of about 150°. The lower window 20 and upperwindow 25 are preferably constructed from glass, plastic or othersuitable material. In an application where it is anticipated objects maystrike the window, it may be coated with a suitable scratch resistantcoating or even constructed of sapphire. The lower and upper windows mayconstitute first and second window elements or may simply be aperturesthrough which the scanning beams pass. The first window element isdefined to be oriented in a first aperture plane and the second windowelement is defined to be oriented in a second aperture plane, the firstaperture plane being oriented at an angle Θ to the second apertureplane. Preferably the angle Θ is greater than 90° and somewhat less than180°, with a preferred angle of 150°.

[0047] Though in actuality the scan patterns generated by each mirrorarray 60, 80 are truly three dimensional, the scanning sweep generatedby each of the mirror arrays may be generally described as a scan plane,the plane being defined by a median of scan lines emanating from therespective mirror array, positioning the plane in a coplanar orientationwith the semicircle of the mirror array. By positioning the mirrorarrays 60, 80 on opposite sides of the polygon mirror 30, the scanplanes emanating from the mirror arrays intersect in the scan volume,the volume through which the objects to be scanned are passed. In anapplication of a vertically oriented scanner in a market checkout stand,the angle of the intersecting scan planes is preferably between about30° and 90° with a preferred angle of about 60°.

[0048] Though the preferred scanning system is described as a fixedscanner with objects bearing a symbol such as a bar code being passedthrough the scan volume, alternately the scanner and the scan volume maybe moved past a stationary object. Such a configuration may be desirablefor inventory management or large object scanning applications forexample. In either the fixed or moving scanner case, the object is beingpassed through the scan volume.

[0049] Alternately, the scanner window (if a single window is employed)or the scanner windows 20, 25 may comprise holographic elements toprovide additional scan pattern directional control. As described above,FIGS. 2-4 illustrate a preferred beam generation and collectionconfiguration. That configuration is also diagrammatically illustratedin FIG. 7. Light source 56 generates a beam of light onto a small aimingmirror 54 which focuses and reflects the light toward one side of therotating polygon mirror 30 which scans the beam across the upper mirrorarray. Light returning from the target is collected by the collectionmirror 52 and directed toward the detector 59. At the same time, thelower light generation and collecting system generates a light beam fromlight source 76 onto an aiming mirror 74 which focuses and reflects thelight toward the opposite side of the rotating polygon mirror 30 whichscans the beam across the lower mirror array. Light returning from thetarget is collected by the collection mirror 72 and directed toward thedetector 79.|

[0050] The configuration may also include additional componentsdepending upon the application. For example, an optical element 58, 78such as an aperture, filter or grating may be positioned in the outgoinglight path to block out undesirable incoming light rays or provide someother desired function.

[0051]FIG. 7 illustrates only one preferred beam generation andcollection configuration, but other configurations may be implemented.By way of example, certain alternate configurations are set forth inFIGS. 8-17 and will now be described.

[0052]FIG. 8 diagrammatically illustrates an alternate light generationand scanning configuration which employs a single light source 216. Thelight source 216 generates a beam of light through a focusing lens 217which focuses the beam to reflect off a small fold mirror 220 which inturn directs the beam to a beam splitter 224. The beam splitter 224 hastwo functions (a) reflecting a portion of the light toward the polygonmirror 230 and (b) allowing a portion of the light to pass through to bedirected by fold mirror 227 toward another side of the polygon mirror230. On either side of the polygon mirror, the light beam is scannedacross the respective mirror array generating the desired scan patterns.Light returning from the target reflects off the respective mirrorarray, the respective side of the polygon mirror 230, and then reflectsoff beam splitter 224 and mirror 227 and is collected by the collectionlens 222 onto detector 219. In this embodiment having only a singledetector 219, the system may require processing electronics for handlingsimultaneous signals. Alternately, the beam splitter 224 and the mirror227 may be provided with a pivoting means or a shutter may be positionedin one or more of the light paths so that only one incoming beam ispermitted at a given instant. Yet another design may comprise specificalignment of the beam splitter 224 and mirrors 227 and 230 so that onlya single incoming signal is received by the detector 219 at a giveninstant. Yet another alternative design may include a separate detectionsystem for the return beam associated with mirror 227.

[0053] Alternately, such a design may be configured with a rotating orpivoting fold mirror (for example in place of the beam splitter 224)which would alternately direct the light beam toward the fold mirror 227or directly to the polygon mirror 230.

[0054] FIGS. 9-10 illustrate an alternate single light sourceconfiguration in which a light source 236 generates a beam of lightwhich is focused by a focusing lens 234 (optional) and directed by afold mirror 238 through a combination lens element 244 having a outgoingbeam lenslet portion 248 and an incoming beam collection lens portion246. The outgoing beam from the fold mirror 238 is focused by thelenslet 248 toward the shutter mirror 250. The shutter mirror 250 is around shutter element rotated by a motor 258. The shutter mirror 250 hasan outer support ring 254 with a portion of its circular surfacecomprising a reflecting mirror portion 252 and the remaining portionbeing a void 256.

[0055] When the mirror portion 252 is aligned in the beam path, thelight beam is reflected toward the polygon mirror 240 and returningsignal is reflected back to the collection lens which focuses thecollected beam onto detector 239. When the void portion 256 is alignedin the beam path, the light beam passes therethrough and is thenreflected off fold mirror 242 toward the polygon mirror 240 andreturning signal is reflected back off the fold mirror 242, passingthrough the void portion 256 and on to the collection lens which focusesthe collected beam onto detector 239. The relative size of the mirrorportion 252 and the void portion 256 may be selected to adjust therelative amount that the upper and lower scanning is operated. In thepreferred embodiment, a majority of the scanning beam would be directedto the upper scanning portion (e.g. 60%-70%) so the mirror portion 252would be a larger arc (216°−252°) than the void portion (144°−108°).

[0056]FIG. 11 illustrates another alternative light scanning andcollecting scheme. Separate light sources 262, 270 each generate a beamof light which is focused by a focusing lens 264, 272 and then passesthrough an aperture 268, 275 in a concave collecting mirror 267, 274.The light beam then is reflected off a respective fold mirror 265, 277and then to either side of the polygon mirror 260. Beams are thenscanned across respective mirror arrays and reflected signals returnreflecting off the polygon mirror 260 facet, off fold mirror 265, 277and then are collected by respective collection mirror 267, 274 todetector 269, 279. One side of the collection system also illustrates anadditional focusing lens 278 in the light path between the collectionmirror 274 and the detector 279 to assist in focusing the collectedsignal beam.

[0057] Though the previous embodiments illustrate a single polygonmirror for the optical scanning element or mechanism, otherconfigurations may be employed such as for example a rotating opticalpolygon of any suitable number of facet mirrors, a rotating holographicdisk, a pair of rotating single facet mirrors, and a pair of pivotingsingle facet mirrors, or any other suitable scanning mechanism. Some ofthese alternate designs will now be discussed.

[0058]FIG. 12 illustrates a scanning system having a first polygonmirror 284 and a second polygon mirror 282 driven by a common motor 280.The first and second polygon mirrors 284 and 282 may be mountedcoaxially on a common shaft 281. The two light generation and detectionschemes are schematically designated as elements 286, 288 and maycomprise any suitable single or dual light source and any suitable lightdetector configuration such as those already described in the aboveembodiments.

[0059] Similarly, FIG. 13 illustrates a light scanning and collectingscheme having a first polygon mirror 292 and a second polygon mirror 294arranged side-by-side. The polygon mirrors 292, 294 may be driven by acommon motor through transmission means in the base 290. The two lightgeneration and detection schemes are schematically designated aselements 296, 298 and may comprise any suitable single or dual lightsource and any suitable light detector configuration such as thosealready described in the above embodiments.

[0060]FIGS. 12 and 13 illustrate two polygon mirror arrangements, butother arrangements may be employed. For example, the polygon mirrors maybe stacked one on top of the other driven on a common shaft. The mirrorsin any multiple mirror configurations may be of different size anddifferent number of facets depending upon the particular application.

[0061]FIG. 14 illustrates yet another alternative light scanning andcollecting configuration. In this configuration, the optical scanningelement comprises a pair of pivoting single facet mirrors 308, 318.Light source 300 generates a beam of light onto a small aiming mirror302 which focuses and reflects the light toward pivoting mirror 308which pivots to scan the beam across the first mirror array. Lightreturning from the target reflects off the first mirror array and thenthe pivoting mirror 308 and is collected by the collection mirror 304and directed toward the detector 306. At the same time, the lower lightgeneration and collecting system generates a light beam from lightsource 310 onto an aiming mirror 312 which focuses and reflects thelight toward the pivoting mirror 318 which pivots to scan the beamacross the second mirror array. Light returning from the target reflectsoff the second mirror array and then the pivoting mirror 318 iscollected by the collection mirror 314 and is directed toward thedetector 316.

[0062]FIG. 15 illustrates yet another alternative light scanning andcollecting configuration. In this configuration, the optical scanningelement comprises a rotating holographic disk 320 mounted on a motor andsupport frame 321. Separate light sources 322, 332 each generate a beamof light which is focused by a respective focusing lens 324, 334 andthen passes through an aperture 327, 337 in a respective concavecollecting mirror 328, 338. The light beam then is reflected off arespective pivoting fold mirror 326, 336 and then to either side of therotating holographic disk 320. Beams are then scanned, reflecting offrespective fold mirrors 327, 337, across respective mirror arrays towardthe target. Return signals are directed through the holographic disk,off pivoting fold mirror 326, 336 and then are collected by respectivecollection mirror 328, 338 to detector 329, 339.

[0063]FIG. 16 illustrates an alternate light scanning and collectingconfiguration employing a single light source 342 which sends a beam oflight toward a small fold mirror 344. Light reflecting off the foldmirror 344 passes through the inner lens portion 347 of lens 346 whichfocuses the outgoing beam toward pivoting or rotating fold mirror 350.Pivoting mirror 350 alternately directs light either toward pivotingfold mirror 352 or pivoting fold mirror 356 depending upon theorientation of the pivoting mirror 350. Light beam from the respectivepivoting fold mirror 352, 356 passes through a respective side of arotating holographic disk 340. Beams passing through the holographicdisk are then scanned, reflecting off respective fold mirrors 354, 358,across respective mirror arrays and reflected signals return beingdirected through the holographic disk, off pivoting fold mirror 352, 356are collected by focusing lens 348 onto detector 359.

[0064]FIG. 17 illustrates yet another alternate light scanning andcollecting configuration, this one employing first and secondholographic disks 360, 370. The two light generation and detectionschemes are schematically designated as elements 362, 372 and maycomprise any suitable single or dual light source and any suitable lightdetector configuration. such as those already described in the aboveembodiments. The first and second holographic elements 360, 370 may bemounted separately and driven by separate motors, but preferably asillustrated may be mounted on a common axis or shaft 368 and rotatablydriven by a single motor 366. The light beam from the first element 362is directed through the first holographic disk 360 and reflected off thefold mirror 364 and scanned across the first mirror array. Similarly,the light beam from the second element 372 is directed through thesecond holographic disk 37 and reflected off the fold mirror 374 andscanned across the second mirror array. Return beams follow the samepath and are detected in respective collection elements.

[0065] The above described scanning and collecting configurations arebut a few examples of suitable configurations. Following the disclosureherein, one skilled in the art may combine portions of some of theconfigurations with other of the configurations.

[0066]FIG. 18 is a flow chart of a preferred light scanning andcollecting processing scheme. A first (bottom) laser diode light source107 and second (top) laser diode light source 105 generate light beamstoward a respective bottom scan head 112 and top scan head 110. Scanbeams from both the top scan head 110 and the bottom scan head 112 arereflected off a common facet wheel 115 or polygon mirror. Since thedesign may employ a common polygon mirror, the system requires only asingle motor assembly resulting in reduced unit size, weight and cost aswell as power consumption. Return signal is collected at top and bottomcollection optics 120 and 122, with the signals processed in respectiveanalog signal processing units 125, 127 and then converted and processedin respective digital processors 130, 132. The processed raw data fromboth digital processors 130, 132 is then input into a firstmicroprocessor 135 where the signals are analyzed and processedtogether. This common processing allows for enhanced efficiency andscanning advantages. For example, a partial bar code scanned by a scanline generated from the top scan head 110 and collection optics 120 maybe stitched together with a partial bar code scanned by a scan linegenerated from the bottom scan head 112 and collection optics 122 toachieve a complete scan. A second microprocessor 140, which may beseparate from or included within the first microprocessor 135, mayoptionally integrate data input from a weigh scale 197. Once processed,data from the processor 140 is output to an application systemillustrated as the point of sale system 195.

[0067]FIG. 19 is a flow chart of an alternate light scanning andcollecting processing scheme. A first (bottom) laser diode light source157 and second (top) laser diode light source 155 generate light beamstoward a respective bottom scan head 162 and top scan head 160. Scanbeams from both the top scan head 160 and the bottom scan head 162 arereflected off a common facet wheel 165. The return signal is collectedat top and bottom collection optics 170 and 172, with the signalsprocessed in respective analog signal processing units 175, 177 and theninput into a multiplex timer circuit 180 so that the bar code signalsfrom the top and bottom may be successively combined and transmitted tothe decoding I/F electronics unit 185. This common processing allows forenhanced efficiency and scanning advantages similar to the previousembodiment. The decoding microprocessor 185 may optionally integratedata input from a weigh scale 147. Once processed, data from theprocessor 185 is output to the point of sale system 145.

[0068] The scanning system may also be combined with a horizontalscanner. FIG. 20 illustrates a combination vertical and horizontalscanner 410. The scanner 410 includes a housing 412 with a lower housingportion 414, an upper housing portion 416, and a lower horizontalhousing portion 418. The scanner 410 generates a scan volume from foursets of scan lines projected from different generally orthogonaldirections, a first set of scan lines emanating downwardly andsidewardly from a first mirror array 490 through the upper inclinedwindow 425, a second set of scan lines emanating sidewardly from thesecond mirror array 480 through the vertical window 420, a third set ofscan lines emanating generally upwardly and sidewardly from a thirdmirror array 470 through horizontal window 427 (away from the upperhousing portion 414), and a fourth set of scan lines emanating generallyupwardly and sidewardly from a fourth mirror array 460 throughhorizontal window 427 (toward the upper housing portion 414).

[0069] Alternately, the scanning systems of FIGS. 1 or 20 may also becombined with a scale unit or a combined scale-scanner unit. In onealternate embodiment, element 427 may be a weigh scale unit providingweight data and as set forth in the flow chart of FIG. 18 for example,the input from the scale electronics 147 may be sent directly into themicroprocessor 140. In yet another alternate embodiment, element 427 maybe a combined weigh scale and scanner unit providing both a thirdscanning sweep and weighing capability. One such combined scale andscanner is disclosed in U.S. Pat. No. 4,971,176 which is herebyincorporated by reference.

[0070] An alternate multiplanar scanner is illustrated in FIGS. 21-39showing a scanner 500 having a housing 510 with a lower horizontalhousing portion 512 and an upper housing portion 516. The scanner 500has two windows namely an upper window 520 arranged in a generallyvertical plane and a lower window 525 arranged in a generally horizontalplane. The upper window 520 and the lower window 525 are arranged at agenerally right angle to one another.

[0071] FIGS. 22-25 illustrate a preferred optical configuration for thescanner of FIG. 21. A single light source shown as a visible laser diode535 generates an optical beam 515 which is collimated and directedtoward beam splitter 538. The beam splitter 538 splits the optical beam515 into a first beam 517 and second beam 518. The first beam 517 isdirected to a fold mirror 536 which reflects the beam 517 through acentral lens focusing portion 533 in lens 532 and to rotating opticalpolygon 530. The optical polygon is rotated by a motor 590 with itsspeed controlled by a suitable controller. The optical polygon 530includes three mirror facets for producing three different scan linesscanning the optical beam across the pattern mirrors. More facets may beemployed and the facet wheel may scan the beam along the same path butdifferent paths are preferred in this embodiment to achieve bettercoverage of scan lines. As the beam 517 is swept across the upper mirrorarray, a first set of scan lines is produced. The upper mirror array iscomprised of mirrors 586, 588 located in the upper housing section 516adjacent the vertical window 520. Routing mirrors 580, 581, 582, 583,and 584 route the scanning beam from the optical polygon 530 to theupper mirror array 586, 588. With the mirror facets on the spinningpolygon mirror 530 positioned at different angles, each routingmirror(s)/array mirror combination will generate three scan lines perrevolution of the polygon mirror 530.

[0072]FIG. 26 is a diagrammatic side view of a scan pattern 610 ofintersecting scan lines as shown in a vertical Y-Z plane in front of thevertical window 520. This first set of scan lines 610 emanates generallysidewardly through the vertical window 520. The pattern of the scanlines 610 are formed as shown in the following table: Routing mirror(s)Array mirror Scan lines 584 588 611, 612, 613 583 586 614, 615, 616 583588 611, 618, 619 582 586 620, 621, 622 580, 584 588 623, 624, 625 581,582 586 626, 627, 628

[0073]FIG. 27 is a diagrammatic side view of a scan pattern 630 ofintersecting scan lines as shown in a vertical Y-Z plane in the scanvolume facing away from the vertical window 520. This second set of scanlines 630 emanates generally sidewardly and upwardly through thehorizontal window 525 toward the vertical window 520. The lines of thescan pattern 630 are formed as shown in the following table: Routingmirror Array mirror Scan lines 566 554 631, 632, 633 572 552 634, 635,636 578 552 637, 638, 639 568 556 640, 641, 642

[0074]FIG. 28 a diagrammatic top view of a scan pattern 650 ofintersecting scan lines as shown in a horizontal X-Z plane in the scanvolume facing the horizontal window 25. This third set of scan lines 650emanates generally upwardly and latterally sidewardly through thehorizontal window 525 with scan lines 651-656 being perpendicular to theplane of the vertical window 520 and scan lines 657-622 being primarilyfor bottom scanning being toward the vertical window 520. The lines ofthe scan pattern 650 are formed as shown in the following table: Routingmirror Array mirror Scan lines 564 560 651, 652, 653 562 558 654, 655,656 576 552 657, 658, 659 574 552 660, 661, 662

[0075]FIG. 28 also shows the second set of scan lines 630 as they arevisible and provide additional scanning coverage in the horizontal planesuch as for scanning the bottom surface of an object being passedthrough the scan volume.

[0076] Moreover, each of the lateral sides of an object being passedthrough the scan volume scanned by lines from more than one of the setsof scan lines. Assuming an orientation of the scanner 500 with theproduct being moved through the scan volume along the “Z” direction(shown in the X, Y, Z directions in FIG. 21), the face of the objectwould be scanned primarily by lines 654-656 from the third set of scanlines 650 through the horizontal window 525 but also by lines 631-633from the second set of scan lines 630 through the horizontal window 525and by lines 620-622 and 626-628 from the first set of scan lines 610through the vertical window 520. Thus a dense coverage of scan lines isachieved for all lateral sides of an object being passed through thescan volume.

[0077]FIG. 29 is a flow chart illustrating the preferred scanningmethod. A light source 535 generated a beam of light 515 which isdivided by a beam splitter 538 into a first beam 517 and a second beam518. Preferably the beam splitter 538 transmits 40% of the beam to oneside of the facet wheel 530 which scans the beam 517 across the firstset of pattern mirrors M₁ for scanning through the vertical window 520and 60% of the beam is reflected and directed to the opposite side ofthe facet wheel 530 and scanned across the second and third sets ofpattern mirrors M₂ and M₃. The portion of the scanning beams returningvia the first set of pattern mirrors M₁ reflect back off the facet wheel530 and are collected by collection optics namely collection lens 532,collection folding mirror 531 and analog PCB with photodiode 537. Theportion of the scanning beams returning via the second and third sets ofpattern mirrors M₂ and M₃ reflect back off the facet wheel 530 and arecollected by collection optics namely collection lens 540, collectionfolding mirror 544 and analog PCB with photodiode 546.

[0078] The separate collection optics permit the simultaneous scanningthrough the horizontal and vertical windows. Separate analog signalprocessors 710, 712 are provided for simultaneously processing theanalog signals from the respective photodiodes. Each signal is thenconverted and processed in a digital processor 714, 716 and then inputinto the microprocessor 725 for final processing and transmittal to thepoint of sale system 730. Alternately, the signals from the analogsignal processors 710, 712 may be routed to a single digital processor720, multiplexed by a switching mechanism 713. Alternately, acombination of the above two embodiments may be used. Buffers (notshown) may be used in the above embodiments.

[0079] An integrated weigh scale may be incorporated into the horizontalhousing portion 512. Such a system is preferably constructed with aconcentric beam system which does not interfere with the placement ofthe horizontal window 525 at the center of a weighing platter. Thesignal from the scale electronics 740 may then be transmitted to themicroprocessor 725 for processing and output to the POS system 730.

[0080] Thus, a scanning system and method for reading data have beenshown and described. It is intended that any one of the disclosedoutgoing light configurations may be combined with any one of thecollecting configurations. Though certain examples and advantages havebeen disclosed, further advantages and modifications may become obviousto one skilled in the art from the disclosures herein. The inventiontherefore is not to be limited except in the spirit of the claims thatfollow.

1. A scanning system for reading symbols on an object being passedthrough a scan volume, comprising: a scanner housing having an upperhousing section and a lower housing section; a first window located inthe upper housing section, the first window being oriented in agenerally vertical plane; a second window located in the lower housingsection, the second window being oriented in a generally horizontalplane; a light source generating a light beam; a scanning opticalelement; a first mirror array located in the upper housing portionadjacent the first window; a second mirror array located in the lowerhousing portion adjacent the second window; a third mirror array locatedin the lower housing portion adjacent the second window; a beam splitterdividing the light beam into a first optical beam and a second opticalbeam, first means for directing the first optical beam to a first sideof the optical scanning element and to a second side of the opticalscanning element, the optical scanning element scanning the firstoptical beam across the first mirror array; second means for directingthe second optical beam along a second optical path toward a second sideof the optical scanning element, the optical scanning element scanningthe second optical beam across the across the second mirror array andthe third mirror array, wherein the first mirror array is constructedand arranged to generate a first pattern of intersecting scan linespassing through the first window and into the scan volume, the secondmirror array is constructed and arranged to generate a second pattern ofintersecting scan lines passing through the second window and into thescan volume, and the third mirror array is constructed and arranged togenerate a third pattern of intersecting scan lines passing through thesecond window and into the scan volume.
 2. A scanning system accordingto claim 1 wherein the optical scanning element scans a majority ofsecond optical beam across the second mirror array.
 3. A scanning systemaccording to claim 1 wherein the scanning system scans a bottom side andall lateral sides of an object placed in the scan volume.
 4. A scanningsystem according to claim 1 wherein the optical scanning element isselected from the group consisting of: a rotating optical polygonmirror, a rotating holographic disk, a first and second rotating singlefacet mirrors, and first and second pivoting single facet mirrors.
 5. Ascanning system according to claim 1 wherein the first mirror arraycomprises a plurality of pattern mirrors arranged in a generallysemicircular configuration.
 6. A scanning system according to claim 1wherein the second mirror array comprises a plurality of pattern mirrorsarranged in a generally semicircular configuration.
 7. A scanning systemaccording to claim 1 wherein the third mirror array comprises aplurality of pattern mirrors arranged in a generally semicircularconfiguration.
 8. A scanning system according to claim 7 wherein thesecond mirror array and the third mirror array together form a generallycircular or oval configuration.
 9. A scanning system according to claim1 further comprising a first detection system which detects a returncarrier signal from the first optical beam, a second detection systemwhich detects a return carrier signal from the second optical beam, anda processor which processes return carrier signal data from both thefirst and second detection systems.
 10. A scanning system according toclaim 1 further comprising: the upper housing portion including aninclined housing portion positioned generally above and to one side ofthe scan volume; a third window located in the upper inclined housingportion, the third window facing generally downwardly and sidewardlyinto the scan volume; a fourth mirror array positioned in the upperinclined housing portion, wherein the optical scanning element scans thefirst optical beam across the first mirror array and the fourth mirrorarray, wherein the fourth mirror array is constructed and arranged togenerate a fourth pattern of intersecting scan lines passing through thethird window and into the scan volume.
 11. A scanning system accordingto claim 1 further comprising a weigh scale positioned generally along ahorizontal plane coplanar with the second window.